Use link aggregation instead of VIPA on IBM i

In the past, the only option to provide redundant Ethernet on dedicated network adapters for IBM i was a VIRTUALIP ‘interface’. Starting with IBM i 7.1 TR3, there is a new feature called Link aggregation. It is much better and much easier for implementation than VIPA.

VIPA configuration requires 2 physical interface, and 3 public IPs. The traffic is routed only thru one interface, while the second is a backup only. Moreover, the configuration process is kind of complicated.

The other option is provision TCP traffic thru VIOS (SEA) to an IBM i host. For someone who has VIOS skills it is easy, but for IBM i stuff, it is usually ‘mission impossible’. Also the SEA brings additional layer, a machine needs extra CPU cycles to handle TCP traffic, and such configuration is not that fast as direct attach adapters .

Some time ago, IBM introduced the link aggregation feature. It allows trunk two physical adapters to a single logical device.

What is needed for such configuration

two physical Ethernet adapters/ports, or two logical ports provisioned by SR-IOV adapters, or two interfaces delivered by two HEA’s

the ports need to be connected to EtherChannel capable switch or switch pair. If you use two switches they must be configured in a Virtual Link Aggregation Group (VLAG) or Virtual Port Channel.

only 1 public IP address

With this configuration you acquire

Resilience – a system is connected thru independent adapters, switches

Performance – both adapters are actively used to handle TCP traffic. If you use two adapters 1 Gb each, theoretically you get 2Gb bandwidth

Below you can see how to configure it

Here is an Lpar with two logical interfaces delivered by two independent SR-IOV adapters.

These ports looks following on the Green screen.

Create a Line Description type *AGG with the specific resources by command.

If your have ports correctly configures on switches, just add a IP address by ADDTCPIFC command. Vary on the interface and start use it.

In my humble opinion , if you don’t want use SEA, Link aggregation with SR-IOV adapters is the most efficient configuration.